If the files you have removed belong to your OS, thats why reinstalling Maya won't fix it since it won't contain a copy of the missing files.

What OS are you using exactly?

If its Windows your using and you can remember what files you've deleted, you can go back to your install disks and then extract the missing files from the archives and into where they are supposed to go. This may not work though since the files may need to be registered by Windows.

You could try recovering your files with file recovery software but since you've mentioned you have modified the contents of your drive after you've removed the files, this is most likely impossible. You'll probaly have to reinstall your entire PC.